JOHN HARDY wrote:
>
> the use of inappropriate technology. Call me picky but I would also
> disapprove of painting a Hepplewhite Dining table to make it easier to
> clean!
Ah yes, but that could start a whole new thread on the various merits of
Hepplewhite vs Louis Quatorze!
Back to the embrittlement, I was taught at CalTech in the 50s (by Linus
Pauling no less) that the embrittlement was caused by the hydrogen
bubbles formed by excess current during plating reacting with the carbon
that turns plain iron into steel. Sharp edged and cornered carbide
crystals formed which created starting points for eventual failure the
same way a sharp radius on a crank journal leads to cracking at the
fillet. By "roasting" the plated part at an elevated temperature for a
period of time the carbide is decomposed and the future stress points
mostly eliminated. Almost all new chrome wire wheels now use stainless
steel spokes and it's not only for ease of cleaning, but for strength as
well.
We had a familiy from South Africa with an MGA pass through the Bay Area
about 25 years ago. They were on a year long round the world honeymoon.
They had stopped in Rhodesia (source of most of the world's chrome at
that time) and an MG host there had his wheels disassembled and chromed
as a wedding gift. Later, going through a tunnel in Norway, he heard a
machine gun which was the sound of 25 of his 48 spokes breaking on his
right rear wheel! When he got to England to have the wheel repaired, he
found out that Dunlop used a heavier spoke when plating a wheel to make
up for the loss of strength... Jarl
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